A/N: thank you for all the follows and favs everyone, it means a lot! Here's another chapter, this one is a little longer but some people had some explaining to do...

She woke up to a very annoying sound. It was a muffled and strangely familiar melody, punctuated by weird sound effects. The young woman groaned at the stabbing pain radiating in the back of her skull. She felt nauseous. Slowly, very slowly, she began to open her eyes. She was resting on a comfortable single bed with long white canopies that were lightly flowing. She cautiously sat up, pushing the curtains aside. She apparently was in an infirmary. There were a dozen other beds in the white tiled room. On the one next to hers, Peter was lying down, legs crossed, playing on a Gameboy. Mario. That's the melody she had recognized.

"Sup" he mumbled without taking his eyes off his game.

There were too many questions hustling in her brain. Where was she? How long had she been here? Where was Ellie? What was this guy doing here? But looking at the mutant next to her, one thought popped up in her mind.

"You knocked me out… with a frying pan!" she cried, more outraged by the second part than the first.

Peter had a loud and quick laugh burst, apparently very proud of himself.

"Yeah. Fun times. To be fair, you almost beheaded me with a kitchen knife, so I say I went easy on you."

At this very moment, she regretted not actually doing it, just to wipe this smirk off his face.

"I want to see Ellie."

"She'll be there with the Professor any minute," he answered, his eyes still glued to his console. "You know, it's pretty exhausting following you around. I usually spend most of my days watching stupid stuff on TV and playing video games in my basement."

"So I see," she mumbled.

"All this walking and working… I don't know how you do it," he added in a monotone voice.

"How long have you been following me, exactly?" she asked, trying her best not to jump on the young man and strangle him. His casualness was infuriating.

"A couple days. Since you moved out of LA."

"Why did they send you?"

"Have you met me? I'm pretty good at going unnoticed."

"No, I mean why would you need to follow me?"

"Xavier has been looking for you. For some reason he couldn't find you with Cerebro. So he sent me. I gotta say, you made my task a whole lot easier by setting this building on fire. It was like a giant "FIND ME HERE" sign."

"I didn't mean to," she whispered. "What's Cerebro?"

"Err, not sure, actually. Some kind of machine he uses to locate people, mutants. Apparently, you didn't pop out. Not clearly enough anyway."

"Why not?"

He shrugged.

"You tell me."

They stopped talking for a few seconds. Then, for the first time, he looked at her and sat up, facing her.

"What happened at that school?"

She felt a flaming shame mixed with rage rising through her. She was opening her mouth to answer when a WHOOSH interrupted her. She let out a first cry of surprise as a few people magically appeared in front of her bed, and a second one when she realized one of them was blue. With 3 fingers on each hand. And a tail. She precipitately backed up against the wall, knocking over the night stand behind her and everything on it.

"I'm so sorry," the blue guy said with a strong German accent. "Did I startle you?"

"Obviously," Peter mumbled while picking up the lamp that had fallen over. "You need to stop doing that bro."

When she realized the weird guy was not a threat, Thea started breathing again. The young blue man waved a three-fingered hand at her and she had a hesitant smile in return. Then she saw Ellie, Charles, Hank and Raven behind him. Smiling, she ran to her. Well, walked very fast. She was still feeling dizzy.

"Are you ok?" she said while hugging her tight.

"Yes," the little girl said back. "I played hide and seek with Kurt. He always wins." she added with a cute laugh.

"So she's your sister" Peter said. "How does that work? Same dad or mom?"

Thea guessed his was talking about their different skin colors.

"Neither. She was adopted" Thea answered while carefully sitting back on the bed. Ellie sat on her lap.

"Thea" Charles said, interrupting their conversation. "We have a lot to talk about. I'm sure you have a lot of questions."

"Oh yes."

"First of all, I would like to apologize for the way you were brought here," he said, glaring at Peter. "It was not supposed to go like this. We are your allies, you have to believe that."

Thea didn't say anything, still upset about this whole situation and anxiously waiting for what was about to follow.

"Look, there is a good reason we brought you here, and there is really no easy way to put this. We worked with your parents, Thea. All their research on induced mutations, we were a part of it. And we think you are the key to finishing it."

She felt like a huge bolder had landed on her stomach. She tried to swallow but her throat was too tight. She was glad to be already sitting down since she felt her knees shaking.

"Ellie honey, why don't you go play with Kurt some more huh?" she said with a weak voice. "We've got some grown up talking to do."

The little girl who was playing with one of Thea's blonde curls looked worried but she nodded without a word. A few seconds later, she disappeared in a WHOOSH with the blue mutant.

"Tell me the truth. Are you responsible for my parents' disappearing?"

"In a way, I am," he answered, a world of regrets in his eyes. "But I'm not the one who took them. I might know who did."

"What do you mean, took them? Are they still alive?"

The room fell completely silent. She looked for an answer in everyone's eyes, but the mutants suddenly found the floor to be very interesting. Even loudmouth Peter was avoiding her stare.

"I can't tell you for sure," Charles finally said.

She felt a torrent of tears threatening to burst out. But she couldn't give in to fear and sorrow. She took a deep, shaky breath.

"Who took them?"

"We believe a man named Stryker to be involved with this. His father worked with the CIA. They both made their loathing for mutants quite clear. This man would do anything to wipe out mutants from this planet, and your parents' invention might just do the trick."

"This Stryker guy, who is he exactly? How do you know he's involved?"

"He's an asshole," said Raven with a fit of rage. "A monster obsessed with power. He uses his connections with the CIA and the US army to get what he wants. And trust me when I say what he wants can never be good for us."

The 3 others nodded, a dark shadow on their faces.

"A few weeks ago," Peter continued, "Stryker was nice enough to take Hank, Raven and me to his little hiding spot. We eventually got the hell out of there but I managed to grab a couple things before leaving," he smirked. "Villains rule number one: Do not bring a kleptomaniac into your super-secret lab."

"Turns out Stryker was onto something big," Hank said, a worried look on his face. "These papers Peter brought back were about a substance that could induce mutations," He paused. "Your parents' names were all over them. Somehow, he stole their research."

Thea's head was spinning. Could she trust these people? Probably not, but they seemed like the lesser of two evils.

"Ok," she calmly said. "But where do I come in? How can I be of any help? Besides resuming my parents' research –which, by the way, I'm already doing- what could I do to stop this guy?"

Charles stared at her.

"There was another name on those papers. Yours."

She remembered what she had found with Robert a few hours earlier. The drawings. The key.

"I don't know anything more than you do. Not yet anyway," she whispered.

"It isn't about what you know. It is about who you are."

"I'm… not sure I'm following."

He came closer to her.

"What exactly are your powers, Thea?"

"I don't really know. I've never really used them on purpose."

"Well, whatever it is, we have good reasons to believe that this… aura inside you is the key to finalize your parents' work."

Confused, she raised her eyes to meet Hank's, who she thought to be the scientist of the group.

"From what I was able to understand," he said, "this molecule they synthesized can interact with the proteins involved with DNA replication and target a particular gene. But it can only be activated with a very specific wave length."

He paused.

"I believe this kind of energy could come from… you."

"How is that even possible?" she asked without really expecting an answer.

Charles gave her a few seconds to comprehend all this information.

"I'm sorry you had to find out this way. But we are running out of time. Stryker probably already knows we are onto him. And if we managed to find you, then so can he. That is why we are offering you a place here, at our School for Gifted Youngsters. We could help you understand and control your abilities while ensuring you and your sister's safety."

Thea observed the four mutants, worried. They were looking back at her, their eyes filled with hope. She could literally feel their minds racing, anxiously waiting for her answer. She didn't want to stay. She didn't feel like she belonged here and she most definitely didn't feel safe. And what kind of life would that be for Ellie? On the other hand, the Professor was right. If this Stryker guy found her, she would be in deep trouble. She sighed, resigned.

"I want to know exactly what you know. No secrets. And trust me, I know when someone is lying to me. I want a fully equipped lab where I can resume my research. And I'll need to personally make sure Ellie will be getting the same education she would have had in a normal school."

Charles nodded with a thin smile.

"Welcome among us. Peter will show you around, and then you should get some rest. Your training will begin tomorrow."

"Great," Peter grumbled. "Now I'm babysitting."

"Play nice," Raven said on an irritated tone before leaving the room, to which Peter responded by mimicking her.

He stood next to the door with a "what-are-we-waiting-for" look. Thea crossed her arms and didn't move.

"You don't have to like me," she said harshly. "And quite frankly, I don't really care. But if your attitude gets in the way of what I'm here for, then we have a problem. Cause apparently, we are going to spend some time together, so we might as well settle things now."

He raised his hands in sign of surrender.

"Hey calm down little miss sunshine, you heard the boss. I'll play nice."

The estate was huge. It took them over half an hour just to visit the building. And they weren't even taking their time. In fact, Peter was only naming the countless rooms they had been passing by without giving any sort of details or explanation. At one point, she saw Ellie playing with a bunch of other kids. She realized with a heavy heart that the fact that she was normal made her the special kid here. And it wouldn't take long for the other children to figure that out. She promised herself to get this whole thing over with as fast as she could.

They finally arrived at the very top of the mansion. At the end of a long hallway, Peter pushed a large sculpted door to enter a spacious and luminous room. Wide and comfortable chairs and couches were arranged around a marble fireplace. There were countless completely full bookshelves, a TV and two computers.

"This is the common room. Only X-men are allowed in here. The two sets of stairs you see back there lead to their rooms. Girls on the right, boys on the left. Your room is up there as well."

"X-men? What is that?"

"You'll find out soon enough. Okay! I think we're done here. Thanks for not asking too many questions and making this less painful than it had to be. Have a good day."

Thea rolled her eyes and left the room after him. When he realized she was following him, he stopped and turned around.

"Er, what are you doing? Your room is the other way. I know I'm not the best tour guide but that's literally the last thing I showed you. Come on now."

She glared at him.

"I'm going back to my place. I need to pick up some stuff. You didn't exactly give me time to pack up before coming here."

"I don't think you're supposed to leave. Xavier might not be cool with that."

She rolled her eyes again and walked past him.

"What are we, 16? Besides, he doesn't have to know."

She felt a draught lifting her long hair and the young man was standing in front of her again, forcing her to stop.

"Nope. Can't let you do that, sorry."

She looked right at him. Her eyes turned from bright blue to bloody red. The paintings and furniture in the hallway started shaking.

"Jeez," he said while taking a step back. "There's no need to go all Wicked-Witch-of-the-West on me. Go, see if I care."

She had a mean smile and resumed walking. She heard Peter let out an annoyed noise.

"But I'm coming with you."

"Ugh, why?" she sighed without stopping.

"If anything happens to you, I'm as good as dead. I'm kind of supposed to look after you."

Great. She had been assigned the most annoying bodyguard they could find. However, after everything she had just learned, she was kind of relieved not having to go out there alone. Although she'd rather die than telling Peter that.

"Fine. Let's go."

A/N: I hope you enjoyed, please don't hesitate to leave a review if you have some suggestions/wants/ideas for how the story should continue. Do you like the OC/Peter dynamic? Something tells me these too are going to spend a little more time together, whether they like it or not...